Answer: 1.90°
Step-by-step explanation:
The small angle formula is given as:
tanθ = D/d
Where
θ = angular diameter;
D = diameter of the earth;
d = distance from moon to the earth.
Therefore, angular diameter, θ, is:
θ = tan⁻¹(D/d)
The (equatorial) diameter of the earth, D, is 12756.2km.
The mean distance of the moon from the earth, d, is 384399km.
Hence,
θ = tan⁻¹(12756.2/384399)
θ = tan⁻¹(0.03318478976272)
θ = 1.90°
Hence, the angular diameter of the earth, using the small angle formula, is 1.90°.